2 * Copyright (C) 2005-2006 Andre Noll <maan@systemlinux.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
19 /** \file alsa_writer.c paraslash's alsa output plugin */
22 * Based in parts on aplay.c from the alsa-utils-1.0.8 package,
23 * Copyright (c) by Jaroslav Kysela <perex@suse.cz>, which is
24 * based on the vplay program by Michael Beck.
32 #include <alsa/asoundlib.h>
34 #include "write.cmdline.h"
37 extern struct gengetopt_args_info conf
;
39 #define FORMAT SND_PCM_FORMAT_S16_LE
41 /** data specific to the alsa writer */
42 struct private_alsa_data
{
43 /** the alsa handle */
45 /** determined and set by alsa_open() */
46 size_t bytes_per_frame
;
50 * open and prepare the PCM handle for writing
52 * Install PCM software and hardware configuration. Exit on errors.
54 static int alsa_open(struct writer_node
*w
)
56 snd_pcm_hw_params_t
*hwparams
;
57 snd_pcm_sw_params_t
*swparams
;
58 snd_pcm_uframes_t buffer_size
, xfer_align
, start_threshold
,
60 unsigned buffer_time
= 0;
64 snd_pcm_uframes_t period_size
;
65 struct private_alsa_data
*pad
= para_malloc(sizeof(struct private_alsa_data
));
66 w
->private_data
= pad
;
68 snd_pcm_info_alloca(&info
);
69 if (snd_output_stdio_attach(&log
, stderr
, 0) < 0)
71 err
= snd_pcm_open(&pad
->handle
, conf
.device_arg
,
72 SND_PCM_STREAM_PLAYBACK
, 0);
75 if ((err
= snd_pcm_info(pad
->handle
, info
)) < 0)
76 return -E_SND_PCM_INFO
;
78 snd_pcm_hw_params_alloca(&hwparams
);
79 snd_pcm_sw_params_alloca(&swparams
);
80 if (snd_pcm_hw_params_any(pad
->handle
, hwparams
) < 0)
81 return -E_BROKEN_CONF
;
82 if (snd_pcm_hw_params_set_access(pad
->handle
, hwparams
,
83 SND_PCM_ACCESS_RW_INTERLEAVED
) < 0)
84 return -E_ACCESS_TYPE
;
85 if (snd_pcm_hw_params_set_format(pad
->handle
, hwparams
, FORMAT
) < 0)
86 return -E_SAMPLE_FORMAT
;
87 if (snd_pcm_hw_params_set_channels(pad
->handle
, hwparams
,
88 conf
.channels_arg
) < 0)
89 return -E_CHANNEL_COUNT
;
90 if (snd_pcm_hw_params_set_rate_near(pad
->handle
, hwparams
,
91 (unsigned int*) &conf
.sample_rate_arg
, 0) < 0)
93 err
= snd_pcm_hw_params_get_buffer_time_max(hwparams
, &buffer_time
, 0);
94 if (err
< 0 || !buffer_time
)
95 return -E_GET_BUFFER_TIME
;
96 PARA_DEBUG_LOG("buffer time: %d\n", buffer_time
);
97 if (snd_pcm_hw_params_set_buffer_time_near(pad
->handle
, hwparams
,
99 return -E_SET_BUFFER_TIME
;
100 if (snd_pcm_hw_params(pad
->handle
, hwparams
) < 0)
102 snd_pcm_hw_params_get_period_size(hwparams
, &period_size
, 0);
103 snd_pcm_hw_params_get_buffer_size(hwparams
, &buffer_size
);
104 PARA_DEBUG_LOG("buffer size: %lu, period_size: %lu\n", buffer_size
,
106 if (period_size
== buffer_size
)
107 return -E_BAD_PERIOD
;
108 snd_pcm_sw_params_current(pad
->handle
, swparams
);
109 err
= snd_pcm_sw_params_get_xfer_align(swparams
, &xfer_align
);
110 if (err
< 0 || !xfer_align
)
112 snd_pcm_sw_params_set_avail_min(pad
->handle
, swparams
, period_size
);
113 /* round to closest transfer boundary */
114 start_threshold
= (buffer_size
/ xfer_align
) * xfer_align
;
115 if (start_threshold
< 1)
117 if (snd_pcm_sw_params_set_start_threshold(pad
->handle
, swparams
,
118 start_threshold
) < 0)
119 return -E_START_THRESHOLD
;
120 stop_threshold
= buffer_size
;
121 if (snd_pcm_sw_params_set_stop_threshold(pad
->handle
, swparams
,
123 return -E_STOP_THRESHOLD
;
124 if (snd_pcm_sw_params_set_xfer_align(pad
->handle
, swparams
,
127 if (snd_pcm_sw_params(pad
->handle
, swparams
) < 0)
129 pad
->bytes_per_frame
= snd_pcm_format_physical_width(FORMAT
)
130 * conf
.channels_arg
/ 8;
131 return period_size
* pad
->bytes_per_frame
;
135 * push out pcm frames
136 * \param data pointer do data to be written
137 * \param nbytes number of bytes (not frames)
139 * \return Number of bytes written, -E_ALSA_WRITE on errors.
141 static int alsa_write(char *data
, size_t nbytes
, struct writer_node
*wn
)
143 struct private_alsa_data
*pad
= wn
->private_data
;
144 size_t frames
= nbytes
/ pad
->bytes_per_frame
;
145 unsigned char *d
= (unsigned char*)data
;
146 snd_pcm_sframes_t r
, result
= 0;
149 /* write interleaved frames */
150 r
= snd_pcm_writei(pad
->handle
, d
, frames
);
152 PARA_ERROR_LOG("write error: %s\n", snd_strerror(r
));
153 if (r
== -EAGAIN
|| (r
>= 0 && r
< frames
))
154 snd_pcm_wait(pad
->handle
, 1);
155 else if (r
== -EPIPE
)
156 snd_pcm_prepare(pad
->handle
);
158 return -E_ALSA_WRITE
;
162 d
+= r
* pad
->bytes_per_frame
;
165 return result
* pad
->bytes_per_frame
;
168 static void alsa_close(struct writer_node
*wn
)
170 struct private_alsa_data
*pad
= wn
->private_data
;
171 snd_pcm_drain(pad
->handle
);
172 snd_pcm_close(pad
->handle
);
173 snd_config_update_free_global();
177 /** the init function of the alsa writer */
178 void alsa_writer_init(struct writer
*w
)
181 w
->write
= alsa_write
;
182 w
->close
= alsa_close
;
183 w
->shutdown
= NULL
; /* nothing to do */